Hey!
I am studying the linear displacement strain transformation by applying FEM solutions and experimental data. Several references make the following approximation:
{d} = [Phi]{q},
{s} = [Ksi]{q},
in which d refers to displacement vector, s to strain, Phi to modal displacement matrix and Ksi to modal strain matrix and q is the modal coordinates.
Therefore via least square approximation
{d} = [Phi]([Ksi]^T[Ksi])^(-1)[Ksi]^T {s}
But to accomplish this I need to reconstruct modal strain matrix [Ksi] from FEM computations. (I am using Nastran/Patran) I can easily obtain displacement modal matrix which comes immeadiately as a result of a modal frequency solvers...but how about the Ksi then?
Any idea???
I am studying the linear displacement strain transformation by applying FEM solutions and experimental data. Several references make the following approximation:
{d} = [Phi]{q},
{s} = [Ksi]{q},
in which d refers to displacement vector, s to strain, Phi to modal displacement matrix and Ksi to modal strain matrix and q is the modal coordinates.
Therefore via least square approximation
{d} = [Phi]([Ksi]^T[Ksi])^(-1)[Ksi]^T {s}
But to accomplish this I need to reconstruct modal strain matrix [Ksi] from FEM computations. (I am using Nastran/Patran) I can easily obtain displacement modal matrix which comes immeadiately as a result of a modal frequency solvers...but how about the Ksi then?
Any idea???